scholarly journals The Arabidopsis homeotic genes APETALA3 and PISTILLATA are sufficient to provide the B class organ identity function

Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 11-22 ◽  
Author(s):  
B.A. Krizek ◽  
E.M. Meyerowitz
Keyword(s):  
Mosaic Virus ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Homeotic Genes ◽  
Identity Function ◽  
Leaf Curling ◽  
Class A ◽  
Organ Identity ◽  
Class B ◽  
Additional Role

The class B organ identity genes, APETALA3 and PISTILLATA, are required to specify petal and stamen identity in the Arabidopsis flower. We show here that the activities of these two genes are sufficient to specify petals and stamens in flowers, in combination with the class A and C genes, respectively. Flowers of plants constitutively expressing both PISTILLATA and APETALA3 under the control of the 35S promoter from cauliflower mosaic virus consist of two outer whorls of petals and inner whorls of stamens. These plants also exhibit vegetative phenotypes that are not present in either of the singly (APETALA3 or PISTILLATA) overexpressing lines. These phenotypes include leaf curling and the partial conversion of later-arising cauline leaves to petals. The presence of additional floral whorls in flowers ectopically expressing APETALA3 and PISTILLATA and the rescue of missing organs in class A mutants by ectopic B function suggest that APETALA3 and PISTILLATA play an additional role in proliferation of the floral meristem.

scholarly journals Quantification of the 35S Promoter in DNA Extracts from Genetically Modified Organisms Using Real-Time Polymerase Chain Reaction and Specificity Assessment on Various Genetically Modified Organisms, Part I: Operating Procedure

2005 ◽  
Vol 88 (2) ◽  
pp. 547-557 ◽  
Author(s):  
Sophie Fernandez ◽  
Chrystèle Charles-Delobel ◽  
Angèle Geldreich ◽  
Georges Berthier ◽  
Francine Boyer ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Real Time ◽  
Genetically Modified Organisms ◽  
Limit Of Detection ◽  
Genetically Modified ◽  
Collaborative Study ◽  
Cauliflower Mosaic Virus ◽  
Performance Criteria ◽  
35S Promoter ◽  
Conserved Sequence

Abstract A highly sensitive quantitative real-time assay targeted on the 35S promoter of a commercial genetically modified organism (GMO) was characterized (sF/sR primers) and developed for an ABI Prism® 7700 Sequence Detection System and TaqMan® chemistry. The specificity assessment and performance criteria of sF/sR assay were compared to other P35S-targeted published assays. sF/sR primers amplified a 79 base pair DNA sequence located in a part of P35S that is highly conserved among many caulimovirus strains, i.e., this consensus part of CaMV P35S is likely to be present in many GM events. According to the experimental conditions, the absolute limit of detection for Bt176 corn was estimated between 0.2 and 2 copies of equivalent genome (CEG). The limit of quantification was reached below 0.1% Bt176 content. A Cauliflower Mosaic Virus control (CaMV) qualitative assay targeted on the ORF III of the viral genome was also used as a control (primers 3F/3R) to assess the presence of CaMV in plant-derived products. The specificity of this test was assessed on various CaMV strains, including the Figwort Mosaic Virus (FMV) and solanaceous CaMV strains. Considering the performance of sF/sR quantification test, the highly conserved sequence, and the small size of the amplicon, this assay was tested in a collaborative study in order to be proposed as an international standard.

Functional analysis of cauliflower mosaic virus 35S promoter: re-evaluation of the role of subdomains B5, B4 and B2 in promoter activity

2007 ◽  
Vol 5 (6) ◽  
pp. 696-708 ◽  
Author(s):  
Simran Bhullar ◽  
Sudipta Datta ◽  
Sonia Advani ◽  
Suma Chakravarthy ◽  
Taru Gautam ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Mosaic Virus ◽  
Promoter Activity ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Cauliflower Mosaic Virus 35S

scholarly journals The Cauliflower Mosaic Virus 35S Promoter Extends into the Transcribed Region

2004 ◽  
Vol 78 (22) ◽  
pp. 12120-12128 ◽  
Author(s):  
Sandra Pauli ◽  
Helen M. Rothnie ◽  
Gang Chen ◽  
Xiaoyuan He ◽  
Thomas Hohn
Keyword(s):  
Mosaic Virus ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Sequence Motifs ◽  
Transcription Start ◽  
Transcriptional Enhancers ◽  
Enhance Gene Expression ◽  
Enhancer Function ◽  
Nucleotide Region ◽  
Cauliflower Mosaic Virus 35S

ABSTRACT A 60-nucleotide region (S1) downstream of the transcription start site of the cauliflower mosaic virus 35S RNA can enhance gene expression. By using transient expression assays with plant protoplasts, this activity was shown to be at least partially due to the effect of transcriptional enhancers within this region. We identify sequence motifs with enhancer function, which are normally masked by the powerful upstream enhancers of the 35S promoter. A repeated CT-rich motif is involved both in enhancer function and in interaction with plant nuclear proteins. The S1 region can also enhance expression from heterologous promoters.

scholarly journals Differential Roles of AC2 and AC4 of Cassava Geminiviruses in Mediating Synergism and Suppression of Posttranscriptional Gene Silencing

2004 ◽  
Vol 78 (17) ◽  
pp. 9487-9498 ◽  
Author(s):  
Ramachandran Vanitharani ◽  
Padmanabhan Chellappan ◽  
Justin S. Pita ◽  
Claude M. Fauquet
Keyword(s):  
Gene Silencing ◽  
Mosaic Virus ◽  
Defense Mechanism ◽  
Fluorescent Protein ◽  
Cauliflower Mosaic Virus ◽  
African Cassava Mosaic Virus ◽  
35S Promoter ◽  
Viral Dna ◽  
Posttranscriptional Gene Silencing ◽  
Cassava Mosaic Virus

ABSTRACT Posttranscriptional gene silencing (PTGS) in plants is a natural defense mechanism against virus infection. In mixed infections, virus synergism is proposed to result from suppression of the host defense mechanism by the viruses. Synergistic severe mosaic disease caused by simultaneous infection with isolates of the Cameroon strain of African cassava mosaic virus (ACMV-[CM]) and East African cassava mosaic Cameroon virus (EACMCV) in cassava and tobacco is characterized by a dramatic increase in symptom severity and a severalfold increase in viral-DNA accumulation by both viruses compared to that in singly infected plants. Here, we report that synergism between ACMV-[CM] and EACMCV is a two-way process, as the presence of the DNA-A component of ACMV-[CM] or EACMCV in trans enhanced the accumulation of viral DNA of EACMCV and ACMV-[CM], respectively, in tobacco BY-2 protoplasts. Furthermore, transient expression of ACMV-[CM] AC4 driven by the Cauliflower mosaic virus 35S promoter (p35S-AC4) enhanced EACMCV DNA accumulation by ∼8-fold in protoplasts, while p35S-AC2 of EACMCV enhanced ACMV-[CM] DNA accumulation, also by ∼8-fold. An Agrobacterium-based leaf infiltration assay determined that ACMV-[CM] AC4 and EACMCV AC2, the putative synergistic genes, were able to suppress PTGS induced by green fluorescent protein (GFP) and eliminated the short interfering RNAs associated with PTGS, with a correlated increase in GFP mRNA accumulation. In addition, we have identified AC4 of Sri Lankan cassava mosaic virus and AC2 of Indian cassava mosaic virus as suppressors of PTGS, indicating that geminiviruses evolved differently in regard to interaction with the host. The specific and different roles played by these AC2 and AC4 proteins of cassava geminiviruses in regulating anti-PTGS activity and their relation to synergism are discussed.

scholarly journals trans-Dominant Inhibition of Geminiviral DNA Replication by Bean Golden Mosaic Geminivirus rep Gene Mutants

1999 ◽  
Vol 89 (6) ◽  
pp. 480-486 ◽  
Author(s):  
Stephen F. Hanson ◽  
Douglas P. Maxwell
Keyword(s):  
Dna Replication ◽  
Mosaic Virus ◽  
Severe Disease ◽  
Western Hemisphere ◽  
Cauliflower Mosaic Virus ◽  
Natural Resistance ◽  
Nucleoside Triphosphate ◽  
35S Promoter ◽  
Suspension Cell Culture ◽  
Dna Nicking

Geminiviruses are a group of single-stranded DNA viruses that cause major losses on a number of important crops throughout the world. Bean golden mosaic virus (BGMV) is a typical bipartite, whitefly-transmitted geminivirus that causes a severe disease on beans (Phaseolus vulgaris) in the Western Hemisphere. The lack of natural resistance to geminiviruses has led to attempts to engineer resistance, particularly through the use of pathogen-derived resistance strategies. The rep gene contains several conserved domains including nucleoside triphosphate (NTP)-binding and DNA-nicking domains and is the only geminiviral gene necessary for replication. Previous analysis by our group and others has demonstrated that the NTP-binding and DNA-nicking domains are necessary for geminiviral DNA replication. The ability of the rep gene and rep gene mutants to interfere with geminiviral DNA replication, when expressed in trans, was examined using a transient assay in a tobacco suspension cell culture system. Wild-type (wt) and mutant rep genes were cloned into plasmids under the control of the cauliflower mosaic virus 35S promoter for in planta expression and coinoculated into tobacco cells with infectious clones of various geminiviruses. The wt rep gene from BGMV-GA was able to support replication of BGMV-GA DNA-B. Several different rep gene mutants, with function-abolishing mutations in the NTP-binding or DNA-nicking domains, were potent trans-dominant inhibitors of geminiviral DNA replication.

scholarly journals Epidermal control of floral organ identity by class B homeotic genes in Antirrhinum and Arabidopsis

Development ◽  
2001 ◽  
Vol 128 (14) ◽  
pp. 2661-2671
Author(s):  
Nadia Efremova ◽  
Marie-Christine Perbal ◽  
Alexander Yephremov ◽  
Winfried A. Hofmann ◽  
Heinz Saedler ◽  
...  
Keyword(s):  
Transgene Expression ◽  
Transgenic Arabidopsis ◽  
Cell Communication ◽  
Cell Types ◽  
Floral Organ ◽  
Epidermal Differentiation ◽  
Homeotic Genes ◽  
Organ Identity ◽  
Class B ◽  
Functional Homologues

To assess the contribution of the epidermis to the control of petal and stamen organ identity, we have used transgenic Antirrhinum and Arabidopsis plants that expressed the Antirrhinum class B homeotic transcription factors DEFICIENS (DEF) and GLOBOSA (GLO) in the epidermis. Transgene expression was controlled by the ANTIRRHINUM FIDDLEHEAD (AFI) promoter, which directs gene expression to the L1 meristematic layer and, later, to the epidermis of differentiating organs. Transgenic epidermal DEF and GLO chimeras display similar phenotypes, suggesting similar epidermal contributions by the two class B genes in Antirrhinum. Epidermal B function autonomously controls the differentiation of Antirrhinum petal epidermal cell types, but cannot fully control the pattern of cell divisions and the specification of sub-epidermal petal cell-identity by epidermal signalling. This non-autonomous control is enhanced if the endogenous class B genes can be activated from the epidermis. The developmental influence of epidermal B function in Antirrhinum stamen development is very limited. In contrast, epidermal B function in Arabidopsis can control most if not all epidermal and sub-epidermal differentiation events in petals and stamens, without any contribution from the endogenous class B genes. Possible reasons for differences in the efficacy of B-function-mediated cell communication between the two species are discussed. Interestingly, our experiments uncovered partial incompatibility between class B functional homologues. Although the DEFICIENS/PISTILLATA heterodimer is functional in transgenic Arabidopsis plants, the APETALA3/GLOBOSA heterodimer is not.

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